1. Field of the Invention
The present invention relates to an X-ray converging mirror located at the vicinity of the X-ray source for reflecting X-ray beams emitted from the X-ray source in an X-ray irradiation position direction in the X-ray irradiation device to provide an improved X-ray system, such as an X-ray analysis microscope.
2. Description of Related Art
In recent years, X-ray analysis microscopes have begun to be used in the analysis of biological tissues, such as plants and small animals as well as minerals or in the field of various analysis and quality control of semiconductor packages and electronic parts.
In an X-ray analysis microscope, it is necessary to irradiate microscopic portions of specimens with fine X-ray beams, which are important for analysis as a probe. Conventionally, fine X-ray beams are generated using a microfocus X-ray tube, such as an X-ray converging mirror for converging and focusing fine X-ray beams at an X-ray irradiation position, for example, ellipsoid of revolution type reflecting mirrors, as shown in Japanese Patent Publications No. Hei 4-6903, Hei 5-27840, and Hei 5-43080 have been used.
FIG. 3 schematically shows an ellipsoid of revolution type reflecting mirror where an X-ray source 4 is installed at a first focal point of the ellipsoid of revolution type reflecting mirror 30. A specimen 32 is installed at a second focal point of the mirror 30. Of the X-beams mitted from the X-ray source 31, those reflected on the reflecting surface of the mirror 30 are all converged to the specimen 32 surface.
However, because X-ray beams impinging in the vicinity of the central portion of the mirror 30, as in the case of X-ray beams shown with numeral 33, have a small incidence angle a with respect to the reflecting surface tangent 34 when an ellipsoid of revolution type mirror 30 is used for an X-ray converging mirror, the reflectivity at the reflecting surface is high and the ratio of the X-rays impinging in the specimen 32 (X-ray efficiency) is high. But in the case of the X-ray beams shown with numeral 35 impinging in the vicinity of the X-ray source 31 of the mirror 30, they have a large incidence angle .beta. with respect to the reflecting surface tangent 36, and a problem exists in that the X-ray permeability at the reflection surface is high and the X-ray efficiency is low.